It does seem troubling for an expensive lens such as the 100-400, especially since it is designed for the GX8, G85, GH5, etc., I would think. I have tried the Olympus 50-200mm lens with the MMF3 adapter -- which is a heavier combination -- and noticed no slippage, but then it was just a brief trial. I haven't seen other complaints about it, but you say there are two or three others on DPReview who had experienced a similar event?
It is random, as I said earlier you can put the lens on, put the camera and lens down, pick it up and the lens is loose.. while shooting in Antarctica and Chile, holding both parts with my hands and zooming, focusing etc.. the viewfinder would go dark, giving the warning that the lens had rotated enough to lose connection to the contacts.
With research, I noted that the body part of the lens mount, has several flat springs to keep the lens mounting face against the body mount face, but these springs cannot keep up with the weight of the Panaleica 100-400 when pointing down. Even when being careful to hold both the lens and camera body to steady it, it will loosen and the warning is the screen goes blank.
It is my opinion, that the weight of the lens can, given the right conditions, compress the flat springs enough to allow the rounded nose of the body locking pin to push back enough to compress and allow the lens to turn.
From DPR
The following information was noted on DPReview under the following thread, with the lens on a GX8. I also have a GX8, but purchased a new G85 to use with the PanaLeica 100-400mm, this has also been my experience.
https://www.dpreview.com/forums/thread/4079065?page=2
HRC2016 wrote:
Make sure you get a good strap to carry this brick of a lens. I've been disappointed with it.
More than that, be carefull not to let it dangle with the weight of the lens on the lens mount!
With my GX8, letting the lens hang from the camera, the weight of the lens actually releases the lens lock! It could easily could all off. I was out shooting when i first got it and noticed it happened numerous times.
This is repeatable and others have mentioned the same thing. I don't know if this is the case with other cameras.
Further in the thread
Trevor Carpenter • Forum Pro • Posts: 13,630
Re: Panasonic Lumix Leica 100-400 zoom...but on which body?
In reply to gary0319 • 3 months ago
gary0319 wrote:
jeffharris wrote:
HRC2016 wrote:
Make sure you get a good strap to carry this brick of a lens. I've been disappointed with it.
More than that, be carefull not to let it dangle with the weight of the lens on the lens mount!
With my GX8, letting the lens hang from the camera, the weight of the lens actually releases the lens lock! It could easily could all off. I was out shooting when i first got it and noticed it happened numerous times.
This is repeatable and others have mentioned the same thing. I don't know if this is the case with other cameras.
Haven't noticed this with my E-M1 or E-M5 II, but thanks for the heads up, I'll be more observant from now on.
The first image is my temporary security bracket and grip, the second was copied from DPR along with the comments above.